Interlocked switches



J. M. WALLACE ETAL INTERLOCKED SWITCHES Filed Octv 7, 1947 F19. 41 32 28 38 a2 34 S I9 70 I6 0 I6 4 /8 l 20 46 I l g I /Z I l 1 5 6 6 WITNESSES: 4 INVENTORS James A4. (a/lace nd Paul 5l/w'us.

Patented Dec. 25, 1951 INTERLOCKED SWITCHES James M. Wallace, East McKeesport, and Paul Silvius, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 7, 1947, Serial No. 778,357

3 Claims. (01. 200-) This invention relates to electrical switches generally, and more especially to means for locking and interlocking a plurality of such switches.

One object of this invention is to provide novel interlocking means readily applicable for interlocking any desired number of electric switches.

Another object of this invention is to provide novel interlocking means for a plurality of similar electric switches whereby adjustment of one such switch to one position prevents operation of others of said switches to a similar position.

Another object of this invention is to provide novel means for releasably looking a plurality of electric switches at one predetermined position.

Another object of this invention is to provide novel interlocking means for a plurality of similar electric switches each having a plurality of operative positions, whereby adjustment of one of said switches to an operative position prevents adjustment of any other switch to a similar position.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of preferred embodirnents thereof, when taken in connection with the attached drawing, in which:

Figure 1 is an elevational view partly in section illustrating a plurality of switches having interlocking and locking means in accordance with thi invention;

Fig. 2 is a top view of the switch assembly shown in Figure 1 with the mounting panel, operating handles and certain of the indicating disks removed;

Fig. 3 is a view of the right-hand end of the switch assembly shown in Fig. 2, with a portion thereof being shown in section; and

Fig. 4 is a partial top view of a modified form of the invention.

There is illustrated on the drawing an assembly of a plurality of switches 2 unitarily supported between a pair of channel support members 4 and 5. Each switch 2 comprises opposed contact supporting walls 8 and 10 secured at their ends to channel supports 4 and 3, respectively, preferably to flange extensions of the channel supports, as by screws or the like. Each switch 2 further includes opposed side walls [2, preferably each fitting in opposed grooves formed in the outer edges of contact supporting walls 8 and 10. Contact supporting walls 8 and [0 which are preferably of an insulating material, such as fiber or a molding insulating material, together with side walls 12 and channel supports 4 and 2 6, form an enclosure and supporting frame for each of the switches 2. Contact supporting walls 8 may have contact fingers l4 (Fig. 3) mounted thereon which are adapted to be connected by bridging contacts I8 mounted on an insulated switch shaft l6 having its opposite ends rotatably mounted in bearings in channel supports 4 and 6. Contact supporting wall l0 may also carry contact fingers 20 adapted to be bridged by bridging contacts l8 on shaft l6 at a diiferent position of the shaft from that at which contact fingers [4 are bridged. Obviously any desired number of contact fingers l4 and 20, and a corresponding number of bridging contacts l8, may

be provided for each switch 2. Preferably each shaft 16 of each switch also carries an index wheel [9 which is notched at positions corresponding to the operative positions of the switch and at a neutral position of the switch intermediate spaced operative positions, so that at these positions resilient index fingers 2| carried on contact supporting wall 8 will engage notches in index wheel I! to retain shaft l6 at that particular position.

As shown in Fig. 1 of the drawing, the switches are arranged in pairs, with the shaft [8 of each switch having a gear 22 secured adjacent its outer end, and with these gears of each pair of switches 2 adapted to be driven by an intermediate drive gear 24 meshing with the gears 22 of that pair of switches. Drive gear 24 is mounted on a stub shaft 26 which is journaled in channel support- 4 and in a bearing support 25 mounted on shafts l6 of one pair of switches 2, andeacl' stub shaft has an integral reduced shaft extension 28 on the outer end of which an operating handle 33 is adapted to be secured.

The entire assembly of switches 2 is adapted to be mounted on a panel, or the like 34, by supporting brackets 32 secured at spaced points along the assembly to channel support 4 in any desired manner, such, for example, as by welding or the like. Supporting brackets 32 may likewise be secured to support panel 34 in any desired manner as by bolting or welding. Preferably disk 33 are adapted to be mounted on the outside of panel 34 over each shaft extension 28 for the purpose of carrying suitable indicia. designating the several positions of the switches actuated by that particular shaft extension.

Switches of this type commonly have two operative positions with an intermediate neutral position at which the contacts are open, and these switches are often used for transferring certain control or measuring apparatus, such as meters or the like. to various circuits for control and measuring purposes. Thus, each switch may be operative to connect certain equipment to at least two different circuits. and the number of switches employed will be determined by the number of circuits to which it may be desired to connect that piece of equipment. In order, however, to insure that when such a piece of equipmentis connected to one circuit that such connection will not be disturbed and that the equipment will not be connected to the other circuit at the same time, interlock means have been provided for preventing such an occurrence. The interlock means comprises a pair of interlock bars 38 and 40 at opposite sides of shaft extensions 28, and extending the entire length of the switch assembly. Interlock bars 38 and 48 preferably have their ends notched to be received beneath the heads of supporting screws 46 for limited longitudinal sliding movement. A coil tension spring 48 is stressed between a clip 52 mounted on one shaft extension 28 and an anchor screw 54 on interlock bar 38 to bias the bar to its normal position, at the left (Figs. 1 and 2). A similar coil tension spring i. is stressed between clip 52 and anchor screw 54 on interlock bar 48 to also bias the latter in the same manner.

Interlock bars 38 and M normally occupy their extreme positions to the left, as viewed in Figs. 1 and 2 of the drawing, and each bar is provided with a number of spaced notches 42 and 44, respectively, corresponding with the number of operating shaft extensions 28. Each operating shaft extension 28 is provided with an interlock fixture 56 secured thereon between the interlock bars, with each fixture 56 having a pair of projections 58 and 63 adapted to cooperate with the notches 42 and 44 of the interlock bars, respectively.

It will be observed that with both interlock bars 38 and 48 at their extreme left-hand position, as viewed in Figs. 1 and 2, to which they are biased by springs 48 and 58. that any switch shaft extension 28 may be turned in either direction to actuate its switch shaft l6 to one operative position. In Fig. 2 the second shaft extension 28 from the right has been rotated clockwise from its neutral position to cause projection 58 on its interlock fixture 56 to engage in the adjacent notch 42 in interlock bar 38 and move this bar to the right. With interlock bar 38 at the position shown in Fig. 2 of the drawing, it will be observed that the bar now blocks clockwise rotation of any of the other operating shaft extensions 28, so that none of them may be moved in a clockwise direction so long as the second operating switch extension from the right remains at its extreme clockwise position. However, while the operating shaft extensions 28 of all other switches are blocked againstclockwise rotation by interlock bar 38, any one of them may be moved in a counterclockwise direction whereby projec-- tion 60 of that operating shaft extension 28 will enter the adjacent notch 44 of interlock bar 48 and move it to the right. Assuming that shaft extension 28 at the extreme left is turned in a counterclockwise direction, then the second, third and fifth switches are blocked by bars 38 and 40 and cannot 'be turned in either direction until either the first or fourth shaft extension 28 is returned to its neutral position.

It will be observed that the interlocking means described above is effective in operation to per-- mit but a single one of a plurality of switches to be rotated to a given operative position at any one time. Moreover, this interlocking is foolproof in nature and easy to operate, and consists of but a few relatively simple parts which perform effective interlocking of the type described for any desired numberof switches. Thus, while ten switches 2 are shown in Figure 1, with these switches paired to be actuated by five shaft extensions 28. it will be obvious that any desired lesser or greater number of switches may be employed either with an operating shaft extension 28 on each switch, or for each pair of switches as illustrated in the drawing. or for any desired number of switches, the only alterration required in the interlocking arrangement being the provision of appropriate lengths for interlock bars 38 and.

If desired, the interlock arrangement deing means to lock interlock bars 38 and 48 at a desired position. Thus, there is illustrated in Figs. 1, 2 and 3 a notch 62 in the outer edge of.

interlock bar 38 and a notch 12 in the outer edge of interlock bar for receiving a projec tion 64 on the outer end of a solenoid plunger 66 controlled by a solenoid coil 68. Preferably solenoid coils 68 are supported from panels 34 as by channel-shaped shaft supporting brackets 10, and the plunger 6'5 of each coil may be biased toward the interlock bar associated therewith by a spring 59 to bias plungers 66 to enter their associated notch 62 or 12 when aligned .therewith. As shown in Fig. 2, interlock bar 38 has its notch 62 positioned to receive its plimger 64 when the interlock bar is at its extreme righthand position wherein one shaft extension 28 has been operated to one operative position of its associated switches with the other shaft extensions 28 being blocked against movement in the same direction. On the other hand, notch H2 in interlock bar 40 is positioned to receive its plunger 64 at the extreme left-hand position of the interlock bar corresponding to the position to which it is biased by its spring 58 wherein none of shaft extensions 28 have been rotated in a counterclockwise direction to their other operative position. In order to release interlock bars 38 and 40 so that shaft extensions 28 may be operated, it is merely necessary to energizeeither one or both solenoid coils 68 to withdraw plungers 66 from their respective notches in their interlock bars.

Instead of the solenoid controlled locking plungers shown in Figs. 1 to 3, key controlled plungers may be used' to lock interlock bars 38 and 40 at predetermined positions, and such an arrangement is illustrated in Fig.- 4 wherein plungers 14 are illustrated as being controlled by so key tumbler locks 13.

Having described preferred embodiments of the invention in accordance with the patent statutes, it is desired that the invention be not limited to these particular embodiments, inas- 85 much as it will be apparent, particularly to persons skilled in the art, that many changes and modifications may be made therein without departing from the broad spirit and scope of this invention. Thus, in addition to varying the 70 number of switches 2 and shaft extensions 28, as pointed out above, additional locking means of at least two different types may be provided, and even other equivalent types of locking means are clearly within the purview of this invention.

Also the switches themselves-need not be of the scribed above may be adapted to use with lockparticular type illustrated but may be of any type having one of two operative positions with an titer-mediate neutral or or! position. Accordingly, it is dcired that this invention be interpreted as broadly as possible and that it be limited only its-required by the prior art.

We claim as our invention:

1. A switch assembly, comprising a plurality of switches each having separable contacts and rotatable operating means for said contacts with the operating means having a neutral position and a closed position at each side of said neutral position wherein the switch contacts are closed, a pair of movable interlock members extending in proximity to all of said switches, means on a rotatable portion of each switch positioned when the switches are at neutral position to be engageable with cooperating means on said interlock members in response to rotation of said switches in opposite directions, respectively, for shifting one of said members from one position to another when any one of said switches is rotated in one direction to closed position and for similarly shifting the other of said members when any one of said switches is rotated in the opposite direction to its other closed postion, each of said members when at its other position having means positioned solely in the path of movement of said rotatable switch means to block movement of the other switches in the same direction, but permitting rotation of such other switches in the opposite direction, and releasable means for locking each of said interlock members at one of its aforesaid positions.

2. A switch assembly, comprising a plurality of switches each having separable contacts and rotatable operating means for said contacts with the operating means having a neutral position and a closed position at each side of said neutral position wherein the switch contacts are closed, a pair of longitudinally slidably mounted interlock bars extending in proximity to all of said switches, said bars having spaced notches positioned, respectively, at one position of each bar to receive a projecting means on a rotatable part of each switch in response to rotation of anyof said switches in opposite directions to shift saint. bars to another position, respectively, said-pro jecting means being located outside of theirfm'? spective notches at the neutral switch positions, and the notches for the other switches positioned out of the path of movement of time projecting means of the other switches when said bars are at such other positions to thereby] block rotation of such other switches solely in';

each direction, respectively.

3. A switch assembly comprising, a plurality of I switches each having separable contacts and movable operating means therefor having three positions, locking means extending into proximity with all of said switches and including one part positioned to be engaged by any of said switches upon movement thereof from one position to another to move said one part to a posi- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 828,089 Craft Aug. 7, 1906 2,101,430 Goldbert et al Dec. 7, 1937 2,372,102 Mahnke Mar. 20, 1945 2,442,766 Garvin June 8, 1948 

